This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cortical inputs reach basal ganglia structures, which project back to thalamus and cortex. Due to the lack of the neurotransmitter dopamine synchronized oscillatory and non-oscillatory activity appears in the basal ganglia which can be measured with local field potential (LFP) recordings. In our primate experiments, we study recordings of LFP changes that are associated with the induction of parkinsonism by treatment with the neurotoxin MPTP. We also studied the local effects of dopaminergic drugs on neuronal synchrony in the basal ganglia nuclei, using a microdialysis/LFP recording probe which allows us to assess the effects of drugs, applied locally via reverse microdialysis, on LFPs in the vicinity of the probe. In this funding period we focused on studies of LFP abnormalities in parkinsonian animals. The studies are carried out in an animal that is undergoing a very slow course of MPTP treatment, combined with careful monitoring of the parkinsonian phenotype. Another animal (the third in this series) is currently being prepared for MPTP treatment. In the last funcitn period we also completed our series of studies of LFP changes produced through blockade of receptors for the inhibitory neurotransmitter GABA in the striatum, and their modulation through the local application of dopamine receptor blockers. GABA receptor blockade induced recurrent large LFP events which were not directly synchronized to neuronal activity in the immediate vicinity of the LFP probe, therefore likely reflecting synchronous synaptic inputs instead. In addition, the study resulted in the creation of a new video analysis method to track wakefulness through observations of eye lid opening.